In beer-taste beverages, raw materials such as malts and hops greatly affect their qualities. For example, hops not only give bitterness to beer-taste beverages but also give refreshing hoppy aroma and a body. Bitterness is attributable to an α-acid in the hops, hoppy aroma attributable to terpenes, and a body attributable to polyphenols, and the like, so that each of them is attributable to various ingredients. Accordingly, the bitterness, the hoppy aroma, and the body of the beer-taste beverages have been conventionally adjusted by selecting the methods of brewing, varieties to be used, and processed products depending upon the hops used.
As the selection of the methods of brewing, when hops are added to a wort boil, quality can be controlled by adding the hops at an initial stage, adding the hops in an intermediary stage, or adding the hops at a second-half of a wort boiling step or after a fermentation step. When added at an initial stage, an α-acid attributable to bitterness is sufficiently isomerized to form an iso-α-acid, so that high-quality bitterness can be extracted. On the other hand, a majority of the terpenes attributable to aroma would evaporate away. When added at a second-half stage, the terpenes attributable to aroma would remain, surely giving a hoppy aroma; however, on the other hand, isomerization of an α-acid would be insufficient, so that the bitterness may possibly not harmonize with the beer. In addition, other methods include dry hopping in which hops are dipped in a fermented and stored liquor. In the case of dry hopping, a fresh aroma distinctively owned by raw hops is given.
As the varieties to be used, hops are roughly classified into bitter varieties having a high α-acid content mainly purposed in giving bitterness, and aroma varieties giving high-quality aroma, and varieties of over 100 are being cultivated in the global markets. By selecting varieties having diversified qualities on these bitterness, aroma and body, a desired beer-taste beverage can be produced.
Here, a hop is a perennial plant belonging to Cannabaceae, and a hop flower thereof (matured non-pollinated pistillate flower) is generally referred to as a hop. The lupulin part of this hop flower (yellow granule) is considered to be a substantial part of the bitterness and aroma of the hop.
In beer-taste beverages, hop processed products having a variety of properties obtained by various processing methods have been used. For example, the hop processed products include “Dry Hop Flowers” in which hops are simply dried; “Hop Pellets Type 90” in which Dry Hop Flowers are pulverized and pelletized; “Hop Pellets Type 45” in which Dry Hop Flowers are lyophilized and pulverized, and a fractionated lupulin fraction is concentrated to form into pellets; and “Hop Extract” in which Hop Pellets Type 90 are subjected to a CO2 extraction to extract bitterness ingredients. Further, as processed products having high degree of purity, as the aroma giving, “Oil-Rich Extract” in which hop pellets are subjected to an ethanol extraction to extract aroma ingredients can be used; as the body giving, “Polyphenol-Rich Pellets” which are by-products discharged during the production of hop extracts, and “Polyphenol-Rich Extract” obtained by concentrating only the polyphenol fraction from Polyphenol-Rich Pellets, and the like can be used. Here, “Type 90” and “Type 45” means that the respective yields are 90% or so, and 45% or so.
On the other hand, the hop bract which is a bract fraction discharged as a by-product during the production of Hop Pellets Type 45 have been usually used as fertilizers for soil improvement and feeds for livestock. In addition, as the techniques using this hop bract, Patent Document 1 discloses that a polyphenol derived from hop bracts has antioxidant action or bubble stabilizing action, anti-corrosive action, deodorant action, action for suppressive metastasis of cancer cells, and topoisomerase inhibiting action, so that polyphenols having high purity are produced from hop bracts, and blended with foodstuff, cosmetics, medicaments, and the like. Patent Publication 2 discloses hop bract tea obtained by roasting hop bracts or a beverage obtained by extracting hop bracts themselves, with hot water or water.